chore: remove dead plugin hook loader

docs/tools/plugin.md

@@ -330,22 +330,29 @@ Plugins export either:
 
 ## Plugin hooks
 
-Plugins can ship hooks and register them at runtime. This lets a plugin bundle
-event-driven automation without a separate hook pack install.
+Plugins can register hooks at runtime. This lets a plugin bundle event-driven
+automation without a separate hook pack install.
 
 ### Example
 
-```
-import { registerPluginHooksFromDir } from "openclaw/plugin-sdk";
-
+```ts
 export default function register(api) {
-  registerPluginHooksFromDir(api, "./hooks");
+  api.registerHook(
+    "command:new",
+    async () => {
+      // Hook logic here.
+    },
+    {
+      name: "my-plugin.command-new",
+      description: "Runs when /new is invoked",
+    },
+  );
 }
 ```
 
 Notes:
 
-- Hook directories follow the normal hook structure (`HOOK.md` + `handler.ts`).
+- Register hooks explicitly via `api.registerHook(...)`.
 - Hook eligibility rules still apply (OS/bins/env/config requirements).
 - Plugin-managed hooks show up in `openclaw hooks list` with `plugin:<id>`.
 - You cannot enable/disable plugin-managed hooks via `openclaw hooks`; enable/disable the plugin instead.